Belt sanding apparatus



Jan. 15, H c

BELT SANDING APPARATUS Filed NOV. 5, 1960 a i "L5 21 J1 2 H :g F.)- 13 9Z5 INVEN TOR. FRA/Vf/J' H. Ailc/mer HTTDRNZ'Y 7 nite This inventionrelates to belt type polishing, buffing or sanding machines and moreparticularly to the type in which the abrasive treated belt oscillates.

One object of my invention is to provide an open end belt which may beused with surfaces which have no opening as for example the interior ofa ring or the rung of an assembled chair.

Another object of my invention is to provide means for easily andquickly installing or removing the belt to replace it with a fresh oneor of a different grade of abrasive.

Still another object of this invention is to provide simple means forchanging the belt with one hand so that the other hand may be free tohold the machine in its working position.

A further object of my invention is to provide a light weight portablemachine which may be attached to a convenient portable source of powersuch as an electric hand drill.

Also another object of my invention is to provide a light weight machinehaving its own source of power incorporated in the machine.

A still further object of my invention is to provide a unique attachableand detachable belt.

Other and further objects of this invention will appear from thespecifications and from the claims hereto annexed and from theaccompanying drawings.

In the drawings:

FIG. 1 shows, in perspective, the belt sander in position for sandingthe rung of an assembled chair.

FIG. 2 shows a side View with one end portion of the belt attached to anoscillating mechanism member.

FIG. 3 is a plan view of the invention as shown in FIG. 2.

FIG. 4 is a vertical end View taken along the lines 44 of FIG. 3 withone end of the belt disengaged.

FIG. 5 is schematic view showing the belt in the position of its longestarc of contact with the convex surface of the specimen to be sanded.

FIG. 6 is schematic view showing the belt in the position of itsshortest arc of contact with the specimen to be sanded.

In the following description and in the claims, various details Will beidentified by specific names for convenience, but they are intended tobe as generic in their application as the art will permit.

In the drawings where like reference characters denote like parts in theseveral figures and in this description, certain specific disclosure ofthe invention is made for purposes of explanation, but it will beunderstood the details may be modified in various respects withoutdeparture from the broader aspects of the invention.

Referring now more particularly to the drawings, reference numeral 10denotes a housing (see FIG. 3) to which is perpendicularly attached apartition 11 terminating into a transverse safety shield 12. A pinionshaft 25 mounted in suitable bearings (not shown) in housing 10 extendsinto one direction through the wall of the housing 10 as 28 in FIG. 3and at the other end carries pinion 21 within the housing 10. Power maybe supplied to the apparatus by connecting an electric hand drill 29 toshaft extension 28 by means of chuck 30 forming part of the electrichand drill. In another embodiment, power may be obtained from anelectric motor (not shown) incorporated in the housing 10.

atent Mounted in suitable bearings (not shown) in housing 10 (see FIG.3) are two disc-gear shafts 24, each carrying a gear 23 located withinthe housing 10 and a disc 13 located outside of the housing 10 andbetween housing 10 and safety shield 12. Pinion 21 meshes with gears 23to drive both gears in the same direction and at same speed.

A crank pin 14 is mounted on each disc 13 (see FIGS. 2 and 3) each pin14 being located the same distance from disc-gear axis or shaft 24. Thedisc-gears 23 are meshed (see FIG. 3) so that the crank pins 14 areangularly displaced from each other which results in a minimum distancebetween the crank pins 14 when in one position as shown in FIG. 5 andconversely as shown in FIG. 6 a maximum distance along a straight linesuch as XY (FIGS. 5 and 6) drawn through the crank pins 14 and thecenters of the disc shafts 24.

Also referring to FIG. 5, it will be observed that when the crank pinsare spaced a minimum distance apart the belt has the maximum arc ofcontact between the belt and the surface of the work to be polished. Nowreferring to FIG. 6, it will be observed that when the crank pins arespaced at a maximum distance apart, the resulting effect is that thesaid are of contact is at its minimum. This enables the sawdust or loosematerial created by the sanding or polishing to be quickly dischargedfrom the surface of the work and not clog up the belt.

As shown in FIG. 2 rotatively mounted on each crank pin 14 is a link 18carrying belt hooks 17 in spaced relation for cooperating with openingsor eyelets 16 in belt 15 to secure belt 15 in its desired rotaryrelation to crank pins 14.

Instead of a disc carrying a crank pin I may use a simple crank (notshown) attached to each disc shaft 24 with the crank pins 14 mounted onthe cranks with equal radii of revolution in which case the cranks arepositioned on their respective shafts 24 so that in each completerevolution of the cranks the crank pins 14 are at a minimum distanceapart and at a maximum distance apart respectively on a straight line(such as XY FIGS. 5 and 6) drawn through the crank pins and centers ofthe disc shafts 24.

In another embodiment, I may omit the pinion 21 and pinion shaft 28 andconnect my electric hand drill or other power source directly to shaft24 and mesh disc gears 24 directly with each other with a 1 to 1 ratioin which case the discs will revolute in opposite directions. Also inthis case my crank pins 14 will be so positioned that when each crank isin a vertical position, they will have an angular displacement of 180with each other.

Referring now to FIG. 2 it will be noticed that the handle 31 is mountedunderneath the housing which not only tends to balance the apparatus bybeing more in line with its center of gravity but it is offset from thecenter line of the belt when the latter is held in a vertical positionas shown clearly in FIG. 1. This offset gives clearance to the operatorshand and also allows the operator to regulate the pressure of the belton the work.

The belt 15 may be impregnated with sand or other abrasive grains asdesired. The belt may also be of material suitable for polishing orbuffing. The belt may be of any suitable flexible material as forexample woven or non-woven fabric capable of holding abrasive materialof the desired fineness. At each end of the belt and for a shortdistance therefrom, reinforcing material 26 is secured to the belt tostrengthen the belt Where the holes or eyelets 16 are inserted forreceiving the belt books 17.

The safety shield 12 comes into use (see FIG. 1) to prevent injury bythe cranks to objects at the end of the work piece as for example chairleg 32.

The partition 11 is necessary to prevent the belt hooks 17 from tanglingwith each other in case the tension on the belt loop is slackened whilethe discs are revolving 3 i (see FIG. 5 for example) and also to holdthe link in a stationary and receptive position to easily engage anddisengage the belt (see FIG. 4);

In operating this apparatus in a situation similar to that disclosed inFIG. 1, the operator places both links 18 against the partition 11 tohold the links 13 so that the eyelets 16 may be easily engaged withcorresponding hooks 17. One end of the belt 15, of course, is notattached until after the belt 15 has been looped over the work 27. Theapparatus is now ready for operation.

While certain novel features of the invention have been disclosedherein, and are pointed out in the annexed claims, it will be understoodthat various omissions, substitutions and changes may be made by thoseskilled in the art Without'departure from the spirit of the invention.

What is claimed is:

1. In a belt polishing device portable to the work to be polished; anopen end abrasive belt; means for reciprocating said belt in asubstantially single plane perpendicular to the axis or the work area tobe polished comprising a pair of cranks rotating in the said plane andsynchronized with each other to give a reciprocating movement to saidbelt attached respectively thereto; means for detachably securing saidbelt to said reciprocating means; and shield means adjacent to saidreciprocating means to prevent outside interference with saidreciprocating means.

2. In the device of claim 1 means for detachably securing said belt tosaid cranks comprising a crank pin mounted on said crank; a linkrotatable at one end on said pin and companion hook and eyelet membersof which one member is carried by the other end of said link and theother member by said belt.

3. The combination in a device as set forth in claim 2 which furthercomprises, a housing for mounting said cranks; a member attached to saidhousing and extending between said cranks to support said shield meansand located in reference thereto so as to provide a rest for one of saidlinks when it is desired to connect said belt.

4. In the device of claim 1 whereby said cranks rotate at the same speedand in the same direction; and said cranks angularly displaced from eachother.

References Qited in the file of this patent UNITED STATES PATENTS1,912,016 Sittner May 30, 1933 2,498,947 Fielding Feb. 28, 19502,556,041 Pick June 5, 1951 2,751,728 Pctit June 26, 1956 FOREIGNPATENTS 573,143 Germany Mar. 27, 1933

1. IN A BELT POLISHING DEVCE PORTABLE TO THE WORK TO BE POLISHED; ANOPEN END ABRASIVE BELT; MEANS FOR RECIPROCATING SAID BELT IN ASUBSTANTIALLY SINGLE PLANE PERPENDICULAR TO THE AXIS OF THE WORK AREA TOBE POLISHED COMPRISING A PAIR OF CRANKS ROTATING IN THE SAID PLANE ANDSYNCHRONIZED WITH EACH OTHER TO GIVE A RECIPROCATING MOVEMENT TO SAIDBELT ATTACHED RESPECTIVELY THERETO; MEANS FOR DETACHABLY SECURING SAIDBELT TO SAID RECIPROCATING MEANS; AND SHIELD MEANS ADJACENT TO SAIDRECIPROCATING MEANS TO PREVENT OUTSIDE INTERFERENCE WITH SAIDRECIPROCATING MEANS.